Corrugated flanges for spools and reels are known for a long time. Exemplary of such flanges are disclosed in US D281,482 to Suzuki et al, U.S. Pat. No. 3,565,363 to Mizuguchi et al., U.S. Pat. No. 5,474,254 to Faulkner, U.S. Pat. No. 1,911,427, U.S. Pat. No. 5,169,086, US D330,506, U.S. Pat. No. 2,597,139, U.S. Pat. No. 4,512,532 and U.S. Pat. No. 6,450,441, among others. These references are incorporated herein by reference in their entireties. Corrugations and ribs are added to the flanges to provide the flanges with more structural integrity, among other properties.
However, the prior art does not contemplate adding undercuts to the flanges or more particularly to the corrugations on the flanges.